The invention relates to electrically powering equipment of gas turbine airplane engines.
A traditional circuit for producing electricity from a gas turbine airplane engine is shown in FIG. 1.
A generator such as an integrated drive generator (IDG) is driven by the engine and delivers electricity to an alternating current bus (AC bus) forming part of the electricity distribution circuit of the airplane. The circuit usually also includes a direct current bus (DC bus) powered from the AC bus via a transformer-rectifier unit (TRU). Particular systems for producing and distributing electricity in airplane electricity networks are described in the following documents in particular: U.S. Pat. No. 5,764,502, U.S. Pat. No. 5,233,286, US 2004/119454, and EP 0 838 396.
Once the engine reaches a certain speed, a full-authority electronic control unit (ECU) module associated with the engine is powered by a generator such as permanent magnet alternator (PMA) mounted on an equipment box mechanically coupled to a turbine shaft of the engine. The ECU is also connected to the DC bus as shown, or in a variant to the AC bus of the airplane electricity circuit in order to be powered until sufficient engine speed has been reached to enable the PMA to deliver the electricity required, or in the event of the PMA failing.
A circuit analogous to that shown in FIG. 1 is to be found in association with each engine of the airplane, thus making a plurality of electricity sources available.
The ECU uses the electricity it receives to enable its components to operate and to excite various members of the engine, such as probes or sensors, electrically-controlled valves, or servo-valves that require only limited amounts of electrical power. As a general rule, the ECU comprises two redundant identical portions (1/2 ECU), or channels.